You can start install once you have the system installation CDROM, CD-KEY, and drivers. Most of the settings can be changed after installation, so you can quickly start the installation by clicking "next".
Please make sure to use firewall or IP sharing hub to separate your computer and the physical network. Because the security holes of the new computer has not yet been repaired by Windows Update, it's easily infected by virus/worms.
Install drivers in stable versions.
The latest ServicePack
The latest DirectX(if needed)
The latest Windows MediaPlayer(if needed)
The latest Windows Messenger or MSN Messenger(if needed)
Backup the system with GHOST(BASE)
Activate Windows Update
Office 2000/XP or Microsoft software
Install Office ServicePack or repair by Office Update
Move your data back
Backup the whole system by GHOST(FULL)
The first backup (BASE) can be used in the future if you want to install software in the latest version. It's only needed for testing and experimentation purposes. Regular users can back up the system only once (FULL).